Gillibrand at Catholic Church Conservation provides a link to photos of roadside shrines in Poland in his post: Poland, still Catholic.

During my time in Poland what impressed me more than the shrines themselves, was that people still doffed their hats, bowed, or crossed themselves when they passed these shrines, even while driving by.

The shrines are often memorials to those executed by the Nazi Germans or the Soviets at those places. If you visit major cities you will see small shrines in the foundations of buildings or plaques in the pavement. Memorials to those killed there.

May they be of Holy Memory.

From a Treatise on Caring for the Dead by Augustine of Hippo (Cap. 2, 3)

Nevertheless, it doth not follow that the bodies of the departed are to be despised, or treated as naught, and specially in the case of just men and faithful; for the bodies of such men were used by their spirits in the life for godly purposes, that is, as organs and vessels of all good works.

…

HENCE, remembrance of the departed, and prayers for them, are tokens of true affection. And since the faithful are moved thereto by filial piety, doubt not that this same remembrance and prayer is profitable unto everyone that so lived in this world, as to attain profit from such things after death.

But even if some necessity permitteth not the body to be buried, or from lack of proper facilities giveth no opportunity for burial in a sacred place, yet should not prayers for the soul of the departed be omitted. The duty of such prayers is taught us by the Church, which hath undertaken, as an obligation, to offer them for all the departed of the Christian and Catholic fellowship in a general commemoration without mention of names.

The Polish American Journal has more information on this subject in Kapliczki: Poland’s Small Treasures.